1. Field of the Invention
The present invention relates to a magnetic head slider used for a magnetic disc unit. Also, the present invention relates to a method of forming lead wires inside the magnetic head slider, especially in a portion containing a microactuator.
In recent years, magnetic disc units have been made compact, their performance has been highly enhanced, and their cost has been reduced. In accordance with the recent tendency, it is desired to develop a thin film magnetic head of high performance and low cost. In order to meet the demand, a horizontal magnetic head (planar magnetic head) has been proposed in which a thin pattern forming surface is arranged in parallel with a flying surface. The reason is described as follows. In the case of a horizontal magnetic head, it is easy to form flying rails having specific shapes. Therefore, it is possible to realize a magnetic head capable of flying stably close to the disc surface, and further it is easy to reduce a portion to be machined in the manufacturing process. Therefore, the cost can be lowered.
In accordance with an increasing demand for enhancing the density of magnetic recording and also in accordance with an increasing demand for reducing the sizes of the head element and the magnetic head slider, problems occur in machining and handling.
2. Description of the Related Art
For the above reasons, the present inventors proposed a magnetic head slider which can be manufactured almost without being machined so that the manufacturing cost can be reduced. This magnetic head slider is disclosed in Japanese Unexamined Patent Publication No. 9-81924, the title of which is xe2x80x9cThin film magnetic head slider and electrostatic actuatorxe2x80x9d. A microactuator is incorporated into this magnetic head slider. Therefore, it is possible to accurately control the head element in the tracking direction and the loading and unloading direction.
The above prior art will be explained below.
FIGS. 1 and 2 are views showing a thin film magnetic head slider of the prior art. FIG. 1 is a perspective view of the slider 10 attached to the head suspension 30, seen from the flying surface side. FIG. 2 is a perspective view of the slider 10, seen from the back (opposite side to the flying surface) thereof, before the slider 10 is attached to the head suspension 30.
A portion of the flying surface layer 11 made of SiO2 or Al2O3 protrudes onto the flying surface side of the slider 10 which is opposed to a recording medium not shown in the drawing. This protruding portion forms two flying rails 15 which extend from the leading end 13 to the trailing end 14 with respect to the recording medium moving in the direction of arrow A. On the leading end 13 side between the two flying rails 15, there is provided a central rail 17. Metallic plating of Ni is conducted on the main body 12 of the slider 10 formed on the back of the flying surface layer 11, and also metallic plating of Ni is conducted on the terminal pad section 18 shown in FIG. 2.
The electrostatic microactuator 20 (tracking mechanism) is formed in a portion of the flying surface 11 between the two flying rails 15 and also between the terminal pad 18 and the outflow end 14.
Although the details are not shown in the drawings, the electrostatic microactuator 20, which utilizes an electrostatic attraction force in its operation, is composed of a movable section and a stationary section. On a side of the movable section which is opposed to the recording medium, there is provided an element mount section. There are provided metallic electrodes between the movable and the stationary section in portions respectively opposed to each other. When voltage is impressed between the electrode on the stationary section side and the electrode on the movable section side, an attractive force is generated, and the head element is moved by the attractive force in a direction perpendicular to the track, and tracking is conducted.
An object of the present invention is to provide a magnetic head slider, in which lead wires can be drawn from the head element, which is mounted on the movable station, to the stationary section (slider body) without interfering with movement of the microactuator, such as disclosed in the above Japanese Unexamined Patent Publication No. 9-81924.
According to the present invention, there is provided a magnetic head slider adapted to be opposed to a recording medium comprising: a medium opposing surface being in contact with or flying above a recording medium; a horizontal type head element having a head film which is parallel to said medium opposing surface; a movable section constituted by a part of said head slider including said head element, said movable section supported on a stationary section including a slider body by means of a support spring so as to be movable within a small limited range at least in a tracking direction or in a load-unload direction with respect to said recording medium; and a lead line extending from said head element mounted on said movable section and made of a flexible lead wire, said flexible lead wire extending from said movable section to said stationary section so as not to obstruct the movement of said movable section with respect to said stationary section.
As described above, the lead wires drawn out from the head element are composed of flexible lead wires, the rigidity of which is lower an that of the support spring. Therefore, movement of the movable section with respect to the stationary section is not obstructed by the lead wires. Further, the lead wires can be foamed simultaneously during the manufacturing process of the magnetic head slider.
The flexible lead wire comprises, in cross-section thereof, a conductor portion and a flexible insulator covering said conductor portion. Particularly, the flexible lead wire comprises three laminated layers including two, upper and lower, flexible insulating layers and a central conductor layer sandwiched between said two flexible insulating layers.
Due to the foregoing, the lead wires, the flexibility of which is sufficiently high, can be formed by means of patterning in the manufacturing process of the magnetic head slider.
The flexible lead wire comprising upper and lower flexible insulating layers and a conductor layer sandwiched between said two flexible insulating layers is substantially in parallel to said medium opposing surface. Also, the flexible lead wire has such a shape that it can be deformed within the same single surface or out of a single surface. In addition, the flexible lead wire is bent at least twice to form a U-shaped portion in the small space between the movable section and the stationary section.
The two, upper and lower, flexible insulating layers comprise a cured photoresist. The horizontal type head element comprises an information recording head element and a reproducing head element.
Due to the foregoing, the rigidity of the flexible lead wires can be further reduced.
According to another aspect of the present invention, there is provided a process for manufacturing a magnetic head slider, the process comprising: forming a sacrifice layer on a substrate; forming, on the sacrifice layer, a flying surface layer and a movable section including a head element layer and, in addition, forming a slider body defining a stationary section; and removing the sacrifice layer to separate the head slider from the substrate; characterized in that, after the flying surface layer and the movable section including the heat element layer are formed and before the slider body is formed, a lead line, which should be extended from the head element mounted on the movable section to the stationary section of the slider body, is formed by patterning.
Due to the foregoing, the formation of the lead wires can be conducted in the wafer patterning process when the slider is manufactured.
The lead line is formed in such a manner that: a first flexible insulating layer is patterned and hard baked; a conductor layer film is patterned on the first flexible insulating layer; and a second flexible insulating layer is patterned and hard baked on the conductor layer, so that said lead line comprises three layers including two, first and second, flexible insulating layers and a central conductor layer sandwiched between the two flexible insulating layers.
Due to the foregoing, it is possible to form flexible lead wires, the flexibility of which is high and the rigidity of which is low.